Tone arm indexing device



y 12, 1953 E- SCHWEITZER 2,638,349

TONE ARM INDEXING DEVICE Filed June 13, 1949 2 Sheets-Sheet l 1:.SCHWEITZER TONE ARM INDEXING DEVICE May 12, 1953 2 Sheets-Sheet 2 FiledJune 15, 1949 INVENTOR.

Patented May 12, 1953 United stares 2,638,349. TUNE ARM INDEXiNG DaviesErich Schweitie'r; Buffalo, Y.-, assign'or to lilarkelEleotricvPz-odiicts, Inez, Bud's-Id,

"FFl-IQE a corporation of'Ne'w York Applicants June 13, 1949, Serial No98 672 3 Claims (C1; 274

This invention relates to a tone arm indexing device fora recordchangeradapted to play vari ous sizes-of disk records and moreparticularly to the manual adjustmentof the positioning or indexingmechanism of the tone arm to brin the stylus of the tone arm into thestarting groove of any selected size of records.

One of the principal objects of the mere tion is to provide such amanual std-Justinent-responsive to the positioning mechanism for thetone arm whichisextremel'y simple-and inexpensive in construction-andWilli-accurately re turnthe stylus to the starting groove of either oitwodifferent sized records.

\ Another object is to provide such-a,-m-anual adjustment which will notitself get out cf adjustmenti Another purpose is to provide suchanad-justment' which is readily set to one or the other of its positionsby one lacking mechanical skill;

Another object is lid-provide amanual adjustment which can bein'eorporatedin a tec ord. changer already l'iavin'g a manual indexingor positioning adjustment for two-sizes oi rec ords for the purpose ofaccommodating a thirdsize of records.

Other objects and advantages of the invention will appearfrom thefollowing description and drawings in which:

Figure 1. is a top plan view, with parts broken away, of a recordchanger having a; tone arm positioning mechanism provided with a m-anualadjustment embodying the present invention to adapt it to. records of.different sizes;

Figure 2 is a fragmentary'vertical section taken on lineZ-il, Figure 1.

Figures 3 and 4' are fragmentary horizontalisections taken on line 3--3,Figure 2-,. Figure show"- ing the position of the' parts tobri-ngthestylus of the tone arm to the startingigroove of; say, a seven inchrecord and. Figure 4 showing the position of the parts to bring thestylus otsithe tone arm to, say, the starting groove-etaten inch record.v

Figure 5 is: an enlarged fragmentary View sinisilar to Figure l andshowing a part of the base plate broken away to showapart of the toneamt positioning mechanism-i the arts being shown in the position inwhich the stylus of the tone arm is positioned above the starting grooveof a seven inch record.

Figure 6 is a: fragmentary view Sifflflfiif' WFlg ure 5 and showing a;subsequent position ofthd parts in which the tone arm is free to"tol-lowtfi- The invention is shown in conjunction with a conventional mmof record changer having a metal base plate Ill supporting aconventional turntable ll' 'i'ev'olvifig around a stationary center post[2 having an offset 13' providing a seat It oir'which'a' stack ofrecords to be played are supported. The turntable H is shown ascarrying'a seven inch record [5 in playing position, this recordb'eingshown as having a marginal starting groove [6 in which the stylusis of the tone arm l9'is positioned when the positioning mechanism isadjusted to play seven inch rec was. The turntable is" also adapted tocarry, say, a ten record 20 in playing position, this ten inchreoor'd'having a starting groove 2!.

The-lowermost record of the stack of either se-venorten inch recordssupported on the shoulden of the center post -2 is pushed off this seatto fall to playing position on the turntable H by a 'me'chanis'mincluding a hollow post 22' housing an actuating lever '23 operating arecord push off mechan sm mounted on the hollow post 22. This push onmechanism forms no part of the present' invention "and hence is notshown.

The tone arm F8 is mounted on a; vertical tone arni shaft or sleeve 2extending through the base plate 10* and ionrnalled in and supported bya tone'arm post 25in any suitable manner; Be- Iow'thebase plate M, anactuating arm 26 is fast to this-vertical'tohe'arm shaft 2s. Thisactuating arni is shown as formed-integrally with a-huld 28 which issplit and provided with a pair (rt-clamping ears 29; at on oppositesides of the split andwhich are-drawn together ty a clamping screw 3| soas to clamp" the huh 28 to the vertical tone-armsl'iaft- 24. Theactuating arm 2 54s of' rectangular formand is short and relanveiybmsuin a horizontal direction as best shown: hit-Figures 3 and 4, 1

This actuating arm 2'6 carries an indexing member ofvertical'pin 32which is manually mev'epie: to we diff-erent positions transversely oi'the' actuating arm. For purpose this inderei t'igf'piii extends througha transverse slot 33 extending vertically through the outer end of theactuating arm 2'6 and i also extends through an arcuate slot 34 in thebase plate In of the record changer; This last slot 3 is concentric withthe axis of thevertical tone arm shaft 24 and above thisslot a fingerpiece or knob 35 is mounte'd-onthe indexing pin 32' by means of whichthis indexing pin can be moved manually to one end or the other of theslot 3-3 in the actuating arm 26;

sound groove oi the record in playing the same: This indexing pin 32 isshown as carriedby" a small adjusting arm 36 fast to the lower end of asmall cylindrical sleeve 38 rotatably mounted on a pin 39 fast to andprojecting upwardly from the actuating arm 26. This pin 39 is locatedalong the centerline of the actuating arm 29 between the slot 33 andvertical tone arm shaft 24 and close to the slot 33 and relativelyremote from the vertical tone arm shaft 24. To yieldingly retain theindexing pin 32 in one end or the other of the slot 33' a helicaltension spring 46 is arranged below the adjusting arm 26 and connectsthe indexing pin 32 with the vertical tone arm shaft 24. It will be seenthat when the indexing pin 32 and its small supporting adjusting arm 36are moved to coincide with the centerline of the actuating arm 26 thespring is on dead center. On moving the indexing pin 32 to either end ofthe slot 33 the spring 40 is brought to a corresponding side of its deadcenter position and hence tends to retain the indexing pin at either endof the slot 33.

Any conventional mechanism synchronized with the completion of theplaying of each record can be provided to engage and moves the indexingpin 32 to swing the tone arm |9 to the inoperative position shown infull lines in Figure 1 and, following the dropping of another recordfrom the center post shoulder M to the turntable II, to engage and movethe indexing pin 32 to swing the tone arm l9 and position its stylus |8above the starting groove l6 or 2| depending upon whether the indexingpin has been manually set at one end or the other of the slot 33. Suchconventional tone arm swinging mechanism is generally illustrated ascomprising a stud 45 secured to and extending downwardly from the baseplate l6 and carrying a horizontally swinging bell crank lever 46 oneend 48 of which is actuated by the usual cam (not shown) which becomes,for a brief interval, operative at the end of the record play. The otherarm 49 of this bell crank lever has pivoted thereto, as indicated at 50,an extension which is held in line with the arm 49 by a side stop 52 onthe arm 49 when the bell crank lever is swinging in a counterclockwisedirection as viewed in Figures 5 and 6, but can swing out of line withthe arm 49 when the bell crank lever 46 is swinging in a clockwisedirection as viewed in these figures. The extension 5| is normally heldin alignment with the arm 49 of the bell crank lever by a helicaltension spring 53 which can be secured at one end to an upstanding ear54 on the extension 5| and. anchored at its other end on the base plateID in any suitable manner.

Another arm 55 is pivotally mounted on the stud 45 and is yieldinglyurged into engagement with an indexing stop 56 by a helical tensionspring 58, the arm 55 being thereby yieldingly urged toward the arm 49of the bell crank lever 46. This stop 56 can be fixed or can beadjustable to, say, ten and twelve inch record indexing positions whilethe indexing pin 32 can be adjusted to, say, ten and seven inch recordindexing positions. This indexing pin 32 is located between the arm 55and the arm 49, 5| of the bell crank lever 46.

The outer end of the arm 55 is shown as carrying an L-shaped lever 66having a laterally extending free arm 6| forming with the other orconnected arm 62 a V-shaped crotch 63 adapted to catch and position thelower end of the indexing pin 32. This connected arm 62 of the L-shapedlever 30 is pivoted adjacent its center, as indicated at 64, to the endof the arm 55 and 4 at its extremity carries a pin 65 to which one endof a link 66 is slidingly fitted. For this purpose the link 66 isprovided at one end with a longitudinal slot 68 through which the shankof the pin 65 extends. The other end of the sliding link 55 is pivoted,as indicated at 69, to the outer end of the arm 49, 5| of the bell cranklever 35.

The L-shaped lever 60 is biased toward one end or the other of itsmovement about its pivot 64 by an expansive toggle spring 76 one end ofwhich is secured to a pin 1! on th L-shaped lever 69 and the other endof which is secured to a pin 12 on the arm 55. This toggle spring 59passes beyond dead center in the movement of the parts Assumin that theoperator desires to play a stack of seven inch records on the spindle,he first holds the tone arm H! and moves the knob or thumb piece 35along the slot 32. in the base plate I6 toward the end thereof markedfor seven inch records as shown in Figure 1. This shifts the indexingpin 32, on which this thumb piece is mounted, along the slot 33 in theactuating arm 26 to the position shown in Figure 3. In so moving alongthe slots 34 and 33 the indexing pin swings with its supporting oradjusting arm 36 around the axis of the pin 39 and carries the helicaltension spring 49 beyond dead center so that this spring yieldinglyholds the indexing pin 32 against the end of the slot 33 shown asengaged in Figure 3. Since this indexing pin has been adjusted to apredetermined arcuate or angular relation to the arm 26 about thevertical axis of the tone arm shaft 24 and since both this arm 28 andthe tone arm l9 are compelled to rotate with this tone arm shaft 24, itwill be seen that the indexing pin 32 has also been adjusted to apredetermined arcuate or angular relation to the tone arm l9 about itsvertical axis of rotation. The length of the slot 33 in this directionis, of course, selected to bring the stylus it into a pisition inregister with the starting groove N5 of a seven inch record |5 on theturntable II in response to the movement of the tone arm positioninmechanism which engages and moves the indexing pin 32.

At the completion of play of each seven inch record l5 on the turntablethe bell crank lever 46 is swung clockwise as viewed in Figures 5 and 6by a cam (not shown) which'becomes operative for an interval as for onerevolution following each record play and when the record changer isinitially started. This clockwise movement of the bell crank lever 46causes its jointed arm 49, 5| to engage the lower end of the indexingpin 32 and move it horizontally in a counterclockwise direction asviewed in Figures 5 and 6 about the axis of the vertical tone arm shaft24. This movement of the indexing pin 32 effects a correspondingcounterclockwise movement of the arm 26 and tone arm shaft 23 as viewedin Figure 3 and also a corresponding counterclockwise movement of thetone arm L9 as viewed in Figure 1. This movement of these partscontinues until the tone arm reaches the full line position shown inFigure 1 in which it is completely removed from the record playing zoneso that the lowermost record of the stack supported on the seat M of thecenterpost l2 can be pushed off this seat by the mechanism (not shown)mounted on the post 22 and to fall upon the turntable It will be notedthat by reason of the spring loaded jointed form of the arm 49, 5| ofthe bell crank lever, if the tone arm l9 is manually restrained duringthis movement to its outermost noperative position no parts will break,the extension-.51; merely swingingoutofi-iline with its bell." crankvlever. arm; 48. against the-resistance of its: spring: 53 to.accommodate "such: restraint of the tone arm .I 9...

At. approximately... the same. timezthat the jointedleverv 49.; 5i soengages the indexingpin 3.2 to startsmovement oizthe tone-arm. l9xto itsontermostiinoperative position, it alsohringsthe pin :fia'to the-nearend'of the. $101168, this. being effected; of; course, by thejointedleverrarmxfim 5.1' pushing, through its pivotpin 6'9,ontheslotted' linlr its. Accordingly. while 'the indexing-pin. 32 sobeing moved by direct engagementof. the jointedarm 49,-,511 to swing.thetone arm l9 out et. the record playing zone; the Leshapedlever 60 isalsou-oeing. pushed; by the slotted link .66, ina clockwise. directionto embrace-theindexingpin 32 When. this L -shaped.lever 60.? soswingsibeyondaposition .where the anchoring pin- H has passed beyond aline: intersecting the pins 64 and 12,.the-togglespring- 10,1'whichtends to spread, is; carriedrbeyond dead center'andhence-acts to urgethe [reshaped lever clockwise. as viewed'in Fignresfi andfi and intocontinued engagement with the indexing. pin. 3.2

Theiinal. part ofthisclockwise movement ofthe jointedllever d9; 5 ithroughthe slotted link- 65', and :tlnsough L.-shaped lever 6d nowrestrained by the -indexing.pin:3i2, moves the lever 55 clockwise,asviewedin Figures: 5. and 6, a short distanee away fromzits. fixedstop56'.

Thezmain cam (not shown) now swings'the bell crank: lever.cownterclochwiseas viewed in Figures: andafin This relievesethepressure; against the arm tdand. permitsits: returnspring 58 to bringthis arm 55 against-the. stop 5.6.: At the-sametimethe indexing pin 32,now engaged in the crotch 63 of the L-shaped lever 60 is moved, by'thepressure ofthe return spring 58,

' clockwise, as viewed. in Figures 5 andfi, about the axis of thevertical tone arm shaft 24 and toits indexed position for a seveninchreoord. This clockwisemovement of the indexing pin 32 swings thetone arm ['9 as viewed from above clockwise to a position where itsstylus I 8" is arranged above the starting groove it Of a seveninchrecord;

The continued"counterclockwise movement of the jointed lever 49, 5|brings the pin 65 to the far end of the slot 68 in the slotted lever 66so as to start the counterclockwise rotation of the L- shaped lever andto free the indexing pin 32 from its crotch 63. At the start of thiscounterclockwise movement of the L-shaped lever 60 the letdown mechanism(not shown) goes into action. Since at this time the indexing pin 32 isin its indexed position for seven inch records, the stylus 18 of thetone arm is set down in the starting groove It of the seven inch recordI5 on the turntable and the tone arm is thereafter held against lateralmovement until playing of the record is completed. This position or" theparts is illustrated in Figure 5.

The continued counterclockwise movement of the jointed lever 49, 51effects a continued counterclockwise movement of the L-shaped lever soas to free the indexing pin 32 and permit it to move with the trackingof the stylus along the playing groove of the record. When the stylus l8of the tone arm I9 is in the starting groove of a seven inch record, theindexing pin 32 is in its indexed position illustrated by full lines inFigures 5 and 6. When the stylus it reaches the end of the playinggroove of the rec ord l5, the indexing pin 32 is in the dotted lineposition shown in Figure 6. During record play thcindexingrpini 32;;mustlie-free, of'coursei to more fremztheafulluto theldotted; positionvshown. in Figure: 6' and the counterclockwise With-r drawal of theheshapezrleverifihefiectsthisob ject.

The. continued counterclockwise movement of the jointed'leve1i49 5l and.L-shapedilever to. causes .the togglespringanchoring pin H to passbeyond. ailine intersecting the. axes of the. pins 64" 311G212."Accordingly-1 the toggle springfiikis again .moved. beyond a dead centerand itsexpan- SiLVBifOIGfi tends to page the l;-shaped lever. 60 to its.inoperative position; shown. in Figure 6, this view showing; the:position. of. the parts. at the start of the described sequencer Whenthe-operator.- desires to play, say, teni-nch records'iibinstead of theseveninch recordsriE, in; addition 2 to. placing ten inch records on thecenterpost. seat M the operator also seizes the tone arm moves thefinger piece =35: toward theend: o-tl1a=base plate slot. ttdesignatedasthe ten inch .recordend in Figural; This: shiits the indexing pin 32;from. position at: oneend. oi. the slot 33. illustrated, in Figure 3-,tothe position illustrated in Figure 4; In so shiftingthe index-.-- ingpin fromlone end. ofrtheslot 33 to the other, the-indexingpin swingsaboutthe pin 39; carry-- ing. the adjusting arm 36 whichv supports in.dexing pin. In so swinging the-springl liiisicar ried beyond dead centerso. that. itnow tends. tohold the indexingpin Mat-the: end of the 33asshownin Figured" In thisiposi-tion. themdexing pin issetto positionthestylust8 above the starting groove-2iof. a ten inchreeord .Zll on. .the:turntable: In 1 other words,-,. the. angular relation ot the tone arm.[Band indexingwpinfli. abouttheir common axis-oithe vertical tone armshaft has been altered so .that-vzhen-the indexing pin 32 hasbeen'movedto the position shownin. Figure5 the-stylus 18 will bepositioned above the. starting groove 2 l. .ofav teninch record 12derr-tire turntable, Inotherrespectsthe sequence-of oporation. is thesame as that previously described.v

From the foregoing it will beseen thatv the present inventionaccomplishes the enumerated.

' obiectsin a very simple and sturdymechanism;

I claim:

1. In a, record changer having a turntable adapted to support records ofdifferent sizes, a vertical tone arm shaft alongside said turntable, atone arm having a stylus and mounted on said tone arm shaft to swinghorizontally therewith, and a positioning mechanism for moving said tonearm horizontally to position said tone arm at the start of each recordplay, the combination therewith of a manual adjustment for indexing saidstylus to a position above the starting groove of either of twodifferent sized records on said turntable in response to the movement ofsaid positioning mechanism, comprising an actuating arm fixed to saidtone arm shaft to swing horizontally therewith, an adjusting arm pivotedon said actuating arm to swing about a vertical axis remote from theaxis of said tone arm. shaft, a vertical indexing pin mounted on thefree end of said adjusting arm and arranged in the path of saidpositioning mechanism to be moved thereby about the axis of said tonearm shaft, a pair of stops on said actuating arm limiting the transversemovement of said indexing pin relative to said adjusting arm andarranged to position said indexing pin at two different positions onsaid actuating arm corresponding to the two different positions of thestarting grooves of said two different sized records and meansrestraining said indexing pin against one or the other of 'said stopscomprising a spring mounted on said actuating arm on the side of thepivot axis of said adjusting arm opposite said adjusting arm andconnected with said adjusting arm to be carried beyond dead center inthe movement of said indexing pin from one of said stops to the other.

2. In a record changer having a turntable adapted to support records ofdifferent sizes, a vertical tone arm shaft alongside said turntable, atone arm having a stylus and mounted on said tone arm shaft to swinghorizontally therewith, and a positioning mechanism for moving said tonearm horizontally to position said tone arm at the start of each recordplay, the combination therewith of a manual, adjustment for indexingsaid stylus to a position above the starting groove of either of twodifferent sized records on said turntable in response to the movement ofsaid positioning mechanism, comprising an actuating arm fixed to saidtone arm shaft to swing horizontally therewith, said actuating arm beingprovided with a transverse slot extending vertically therethrough, anadjusting arm pivoted to said actuating arm to swing about a verticalaxis disposed intermediate said slot and said tone arm shaft, a verticalindexing pin fast to said adjusting arm and extending through said slotand arranged in the path of said positioning mechanism to be movedthereby about the axis of said tone arm shaft, the ends of said slotlimiting the movement of said indexing pin and adjusting arm to positionsaid indexing pin at two different positions on said actuating armcorresponding to the two different positions of the starting grooves ofsaid two different sized records.

3. In a record changer having a base plate, a turntable above said baseplate and adapted to support records of different sizes, a vertical tonearm shaft journalled in said base plate alongside of said turntable andextending above and below said base plate, a tone arm having a stylusand mounted above said base plate on said tone arm shaft to swinghorizontally therewith, and a positioning mechanism below said baseplate for moving said tone arm horizontally to position said tone arm atthe'start of each record play, the comibnation therewith of a manualadjustment for indexing said stylus to a position above the startinggroove of either of two different sized records on said turntable inresponse to the movement of said positioning mechanism, comprising anactuating arm fixed below said base plate to said tone arm shaft toswing horizontally therewith, said actuating arm being provided with atransverse slot extendin vertically therethrough, an adjusting armpivoted to said actuating arm to swing about a vertical axis disposedintermediate said slot and said tone arm shaft, a vertical indexing pinfast to said adjusting arm and extending through said slot and arrangedin the path of said positioning mechanism to be moved thereby about theaxis of said tone arm shaft, the ends of said slot limiting the movementof said indexing pin and adjusting arm to position said indexing pin attwo different positions on said actuating arm corresponding to the twodifferent positions of the starting grooves of said two different sizedrecords, a spring secured to said actuating arm intermediate said pivotaxis of said adjusting arm and said tone arm shaft and connected withthe free end of said adjusting arm to be carried beyond dead center inthe movement of said indexing pin from one end of said slot to the otherthereby to yieldingly restrain said indexing pin at one end or the otherof said slot, said indexing pin extending upwardly through another slotprovided in said base plate, and a finger knob on said indexing pinabove said base plate to facilitate adjustment of said indexin pin fromone end to the other of said first slot.

ERICH SCHWEI'IZER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,246,130 Forstrom June 17, 1941 2,295,460 Farrow -1 Sept. 8,1942 2,300,149 Guedon Oct. 27, 1942 2,328,703 Becwar Sept. 7, 19432,517,165 Ascoli Aug. 1, 1950

